High-dose IV ascorbic acid therapy in CCUS patients with TET2 mutations.

This was a phase II trial, evaluating the safety/efficacy of high-dose IV-ascorbic acid in patients with TET2 mutant CCUS. Eight of 10 patients enrolled were eligible for response assessment. At week 20, there were no responses by IWG MDS criteria. NCT03418038.

PHF6 mutations in chronic myelomonocytic leukemia identify a unique subset of patients with distinct phenotype and superior prognosis.

The current study was inspired by observations from exploratory analyses of an institutional cohort with chronic myelomonocytic leukemia (CMML; N = 398) that revealed no instances of blast transformation in the seven patients with plant homeodomain finger protein 6 (PHF6) mutation (PHF6MUT). A subsequent Mayo Clinic enterprise-wide database search identified 28 more cases with PHF6MUT. Compared with their wild-type PHF6 counterparts (PHF6WT; N = 391), PHF6MUT cases (N = 35) were more likely to co-express TET2 (89% vs. 45%; p < .01), RUNX1 (29% vs. 14%; p = .03), CBL (14% vs. 2%; p < .01), and U2AF1 (17% vs. 6%; p = .04) and less likely SRSF2 (23% vs. 45%; p < .01) mutation. They were also more likely to display loss of Y chromosome (LoY; 21% vs. 2%; p < .01) and platelets <100 × 109/L (83% vs. 51%; p < .01). Multivariable analysis identified PHF6MUT (HR 0.28, 95% CI 0.15-0.50) and DNMT3AMUT (HR 5.8, 95% CI 3.3-10.5) as the strongest molecular predictors of overall survival. The same was true for blast transformation-free survival with corresponding HR (95% CI) of 0.08 (0.01-0.6) and 9.5 (3.8-23.5). At median 20 months follow-up, blast transformation was documented in none of the 33 patients with PHF6MUT/DNMT3AWT but in 6 (32%) of 19 with DNMT3AMUT and 74 (20%) of 374 with PHF6WT/DNMT3AWT (p < .01). The specific molecular signatures sustained their significant predictive performance in the context of the CMML-specific molecular prognostic model (CPSS-mol). PHF6MUT identifies a unique subset of patients with CMML characterized by thrombocytopenia, higher prevalence of LoY, and superior prognosis.

RNA shielding of P65 is required to potentiate oncogenic inflammation in TET2 mutated clonal hematopoiesis.

TET2 mutations (mTET2) are common genetic events in myeloid malignancies and clonal hematopoiesis (CH). These mutations arise in the founding clone and are implicated in many clinical sequelae associated with oncogenic feedforward inflammatory circuits. However, the direct downstream effector of mTET2 responsible for the potentiation of this inflammatory circuit is unknown. To address this, we performed scRNA and scATAC-seq in COVID-19 patients with and without TET2-mutated CH reasoning that the inflammation from COVID-19 may highlight critical downstream transcriptional targets of mTET2. Using this approach, we identified MALAT1, a therapeutically tractable lncRNA, as a central downstream effector of mTET2 that is both necessary and sufficient to induce the oncogenic pro-inflammatory features of mTET2 in vivo. We also elucidate the mechanism by which mTET2 upregulate MALAT1 and describe an interaction between MALAT1 and P65 which leads to RNA "shielding" from PP2A dephosphorylation thus preventing resolution of inflammatory signaling.

Acute kidney injury, an underrecognized feature of VEXAS syndrome.

OBJECTIVES: VEXAS syndrome is an autoinflammatory disease caused by somatic mutation of UBA1 and affects multiple organ systems. Involvement of the kidneys is not well characterized. We aimed to investigate the incidence, risk factors and histopathologic features of acute kidney injury (AKI) in VEXAS syndrome. METHODS: Patients with genetically confirmed UBA1 mutation consistent with VEXAS were included. Charts were manually reviewed. Cox regression analysis was used to identify variables associated with time-to-first acute kidney injury (AKI) event. For patients with a kidney biopsy, histopathologic findings were reviewed. RESULTS: Eighty-one patients were included, all white men, with a mean age of 66.3±8.6 years. Median (IQR) follow up was 3.5 (2.1-5.2) years during which 20 (25%) developed AKI and 22% died. AKI relapsed in 90% of cases for a median of 6 times during the follow up period. Cumulative incidence estimates (95% CI) for AKI at 1, 3 and 5 years were 6.2% (0.80-11.3%), 16.7% (7.5-25.0%) and 27.9% (14.9-38.9%), respectively. Age and baseline C-reactive protein were significantly associated with time-to-first AKI event. Six patients underwent a kidney biopsy. Findings included, plasma cell-rich interstitial nephritis (n = 3), neutrophilic-rich interstitial inflammation (n = 1), leukocytoclastic peritubular capillaritis (n = 1), and acute tubular injury (n = 1). AKI responded well to treatment with glucocorticoids but had relapse upon tapering. CONCLUSION: AKI is an underrecognized feature of VEXAS occurring in 25% of patients in this cohort. Age at diagnosis and CRP were associated with time to first AKI event during follow up. Plasma cell-rich interstitial nephritis was the most common histopathologic finding.

Clonal Hematopoiesis in Patients With Neuroendocrine Tumor Treated With Lutetium-177 and the Risk of Thrombocytopenia: A Prospective Study.

PURPOSE: Thrombocytopenia is a relatively common dose-limiting toxicity during peptide receptor radionuclide therapy (PRRT) in patients with NET. Although uncommon, some patients develop persistent cytopenia and eventually therapy-related myeloid neoplasm (t-MN), which has a dismal prognosis. As the indications for PRRT are expanding, it is important to investigate factors that may predict cytopenias during/after PRRT. We prospectively evaluated the prevalence of clonal hematopoiesis (CH) and cytopenia in patients with NET undergoing PRRT. MATERIALS AND METHODS: Patients with metastatic NET with plan to receive four cycles of lutetium-177 were enrolled. CH was evaluated before PRRT using a panel of 220 genes with a targeted depth of ≥1,000×. Patients were followed during PRRT and every 3 months thereafter. RESULTS: Of 37 patients enrolled, the median age was 68 years and 51.4% were male. Previous treatment exposures included alkylating agents in 30%, platinum agents in 8%, and external radiation in 13%. CH was detected in 35.1% using a variant allele frequency (VAF) cutoff of ≥2% and 45.9% with a VAF of ≥1%. The most common mutations were in age-related genes (DNMT3A, TET2). CH was not associated with anemia or neutropenia; however, it was associated with lower platelet count at baseline and more time spent in a thrombocytopenic state during/after PRRT. Five patients had bone marrow biopsies (BMBs) because of sustained hematologic dysfunction post-PRRT, and of those, diagnoses included clonal cytopenia of undetermined significance (CCUS) in three and idiopathic cytopenia of undetermined significance (ICUS) in two. CONCLUSION: CH is present in 35.1% of patients with NET and is associated with thrombocytopenia risk during PRRT. Future studies with long-term follow-up will delineate whether CH might be a predictor for higher risk of t-MN after PRRT.

The impact of cytotoxic therapy on the risk of progression and death in clonal cytopenia(s) of undetermined significance.

ABSTRACT: Clonal cytopenia of undetermined significance (CCUS) is defined by a myeloid driver mutation in the context of otherwise unexplained cytopenia. CCUS has an inherent risk of progressing to myeloid neoplasm. However, it is unknown how exposure to previous cytotoxic therapy may impact the risk of progression and survival. We stratified patients with CCUS by prior exposure to DNA-damaging therapy. Of 151 patients, 46 (30%) had received cytotoxic therapy and were classified as therapy-related CCUS (t-CCUS), whereas 105 (70%) had de novo CCUS. A lower proportion of t-CCUS had hypercellular marrows (17.8% vs 44.8%, P = .002) but had higher median bone marrow blast percentages. After a median follow-up of 2.2 years, t-CCUS had significantly shorter progression-free survival (PFS, 1.8 vs 6.3 years; hazard ratio [HR], 2.1; P = .007) and median overall survival (OS; 3.6 years vs not reached; HR, 2.3; P = .007) compared with CCUS. Univariable and multivariable time-to-event analyses showed that exposure to cytotoxic therapy independently accounted for inferior PFS and OS. Despite the similarities in clinical presentation between CCUS and t-CCUS, we show that exposure to prior cytotoxic therapies was an independent risk factor for inferior outcomes. This suggests that t-CCUS represents a unique clinical entity that needs more stringent monitoring or earlier intervention strategies.

Venous and arterial thrombosis in patients with VEXAS syndrome.

ABSTRACT: VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome, caused by somatic mutations in UBA1, is an autoinflammatory disorder with diverse systemic manifestations. Thrombosis is a prominent clinical feature of VEXAS syndrome. The risk factors and frequency of thrombosis in VEXAS syndrome are not well described, due to the disease's recent discovery and the paucity of large databases. We evaluated 119 patients with VEXAS syndrome for venous and arterial thrombosis and correlated their presence with clinical outcomes and survival. Thrombosis occurred in 49% of patients, mostly venous thromboembolism (VTE; 41%). Almost two-thirds of VTEs were unprovoked, 41% were recurrent, and 20% occurred despite anticoagulation. The cumulative incidence of VTE was 17% at 1 year from symptom onset and 40% by 5 years. Cardiac and pulmonary inflammatory manifestations were associated with time to VTE. M41L was positively associated specifically with pulmonary embolism by univariate (odds ratio [OR]: 4.58, confidence interval [CI] 1.28-16.21, P = .02) and multivariate (OR: 16.94, CI 1.99-144.3, P = .01) logistic regression. The cumulative incidence of arterial thrombosis was 6% at 1 year and 11% at 5 years. The overall survival of the entire patient cohort at median follow-up time of 4.8 years was 88%, and there was no difference in survival between patients with or without thrombosis (P = .8). Patients with VEXAS syndrome are at high risk of VTE; thromboprophylaxis should administered be in high-risk settings unless strongly contraindicated.

Prognostic relevance of clonal hematopoiesis in myeloid neoplastic transformation in patients with follicular lymphoma treated with radioimmunotherapy.

While novel radioisotope therapies continue to advance cancer care, reports of therapy-related myeloid neoplasms (t-MN) have generated concern. The prevalence and role of clonal hematopoiesis (CH) in this process remain to be defined. We hypothesized that: (i) CH is prevalent in relapsed follicular lymphoma and is associated with t-MN transformation, and (ii) radiation in the form of radioimmunotherapy (RIT) plays a role in clonal progression. In this retrospective cohort study, we evaluated the prevalence and prognostic impact of CH on clinical outcomes in 58 heavily pre-treated follicular lymphoma patients who received RIT. Patients had been given a median of four lines of therapy before RIT. The prevalence of CH prior to RIT was 46%, while it was 67% (P=0.15) during the course of RIT and subsequent therapies in the paired samples. Fourteen (24%) patients developed t-MN. Patients with t-MN had a higher variant allele fraction (38% vs. 15%; P=0.02) and clonal complexity (P=0.03) than those without. The spectrum of CH differed from that in age-related CH, with a high prevalence of DNA damage repair and response pathway mutations, absence of spliceosome mutations, and a paucity of signaling mutations. While there were no clear clinical associations between RIT and t-MN, or overall survival, patients with t-MN had a higher mutant clonal burden, along with extensive chromosomal abnormalities (median survival, afer t-MN diagnosis, 0.9 months). The baseline prevalence of CH was high, with an increase in prevalence on exposure to RIT and subsequent therapies. The high rates of t-MN with marked clonal complexities and extensive chromosomal damage underscore the importance of better identifying and studying genotoxic stressors accentuated by therapeutic modalities.

Adaptive and Maladaptive Clonal Hematopoiesis in Telomere Biology Disorders.

PURPOSE OF REVIEW: Telomere biology disorders (TBDs) are germline-inherited conditions characterized by reduction in telomerase function, accelerated shortening of telomeres, predisposition to organ-failure syndromes, and increased risk of neoplasms, especially myeloid malignancies. In normal cells, critically short telomeres trigger apoptosis and/or cellular senescence. However, the evolutionary mechanism by which TBD-related telomerase-deficient cells can overcome this fitness constraint remains elusive. RECENT FINDINGS: Preliminary data suggests the existence of adaptive somatic mosaic states characterized by variants in TBD-related genes and maladaptive somatic mosaic states that attempt to overcome hematopoietic fitness constraints by alternative methods leading to clonal hematopoiesis. TBDs are both rare and highly heterogeneous in presentation, and the association of TBD with malignant transformation is unclear. Understanding the clonal complexity and mechanisms behind TBD-associated molecular signatures that lead to somatic adaptation in the setting of defective hematopoiesis will help inform therapy and treatment for this set of diseases.

VEXAS syndrome: Clinical, hematologic features and a practical approach to diagnosis and management.

VEXAS (Vacuoles, E1 enzyme, X-linked, Autoinflammatory, Somatic) syndrome is a newly identified disease caused by somatic alterations in UBA1 which produce a recalcitrant inflammatory state along with hematologic disturbances. Patients with VEXAS can have a wide spectrum of clinical symptoms and providers should be familiar with the heterogeneity of associated clinical features. While hematologic parameters may be generally non-specific, peripheral blood features of macrocytosis, monocytopenia, and/or thrombocytopenia coupled with bone marrow vacuolization of erythroid or myeloid precursors should raise suspicion for this condition. Due to an increased mortality, prompt recognition and accurate diagnosis is paramount. Access to testing for confirmation of UBA1 variants is not yet universally available but clinicians should understand the current available options for genetic confirmation of this disease. Treatment options are limited due to lack of prospective clinical trials but cytokine directed therapies such as interleukin-6 inhibitors and JAK-STAT inhibitors as well as hypomethylating agents such as azacitidine have shown evidence of partial effect. Though cases are limited, allogeneic stem cell transplantation holds promise for durable response and potential cure. The intent of this review is to outline the pathophysiology of VEXAS syndrome and to provide a practical approach to diagnosis and treatment.

Patients with telomere biology disorders show context specific somatic mosaic states with high frequency of U2AF1 variants.

Somatic mosaic states in telomere biology disorders are characterized by somatic variants in the spliceosome and DNA damage response and repair pathways. A likely maladaptive response to short telomeres that may lead to increased hematological cancer.

Characterization and Optimization of Multiomic Single-Cell Epigenomic Profiling.

The snATAC + snRNA platform allows epigenomic profiling of open chromatin and gene expression with single-cell resolution. The most critical assay step is to isolate high-quality nuclei to proceed with droplet-base single nuclei isolation and barcoding. With the increasing popularity of multiomic profiling in various fields, there is a need for optimized and reliable nuclei isolation methods, mainly for human tissue samples. Herein we compared different nuclei isolation methods for cell suspensions, such as peripheral blood mononuclear cells (PBMC, n = 18) and a solid tumor type, ovarian cancer (OC, n = 18), derived from debulking surgery. Nuclei morphology and sequencing output parameters were used to evaluate the quality of preparation. Our results show that NP-40 detergent-based nuclei isolation yields better sequencing results than collagenase tissue dissociation for OC, significantly impacting cell type identification and analysis. Given the utility of applying such techniques to frozen samples, we also tested frozen preparation and digestion (n = 6). A paired comparison between frozen and fresh samples validated the quality of both specimens. Finally, we demonstrate the reproducibility of scRNA and snATAC + snRNA platform, by comparing the gene expression profiling of PBMC. Our results highlight how the choice of nuclei isolation methods is critical for obtaining quality data in multiomic assays. It also shows that the measurement of expression between scRNA and snRNA is comparable and effective for cell type identification.

Targeting BET Proteins Downregulates miR-33a To Promote Synergy with PIM Inhibitors in CMML.

PURPOSE: Preclinical studies in myeloid neoplasms have demonstrated efficacy of bromodomain and extra-terminal protein inhibitors (BETi). However, BETi demonstrates poor single-agent activity in clinical trials. Several studies suggest that combination with other anticancer inhibitors may enhance the efficacy of BETi. EXPERIMENTAL DESIGN: To nominate BETi combination therapies for myeloid neoplasms, we used a chemical screen with therapies currently in clinical cancer development and validated this screen using a panel of myeloid cell line, heterotopic cell line models, and patient-derived xenograft models of disease. We used standard protein and RNA assays to determine the mechanism responsible for synergy in our disease models. RESULTS: We identified PIM inhibitors (PIMi) as therapeutically synergistic with BETi in myeloid leukemia models. Mechanistically, we show that PIM kinase is increased after BETi treatment, and that PIM kinase upregulation is sufficient to induce persistence to BETi and sensitize cells to PIMi. Furthermore, we demonstrate that miR-33a downregulation is the underlying mechanism driving PIM1 upregulation. We also show that GM-CSF hypersensitivity, a hallmark of chronic myelomonocytic leukemia (CMML), represents a molecular signature for sensitivity to combination therapy. CONCLUSIONS: Inhibition of PIM kinases is a potential novel strategy for overcoming BETi persistence in myeloid neoplasms. Our data support further clinical investigation of this combination.