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Background: Doxorubicin (DOX)-induced cardiotoxicity (DICT) has become a serious health burden for cancer survivors. The detrimental effects of CXCR4-mediated excessive inflammation in myocardium and the protective effects of CXCR7 in cardiomyocytes have been demonstrated. Aims: We tested the protective effects against DICT of a dual-targeting compound TC14012, which has specific antagonistic activity against CXCR4 and potent agonistic activity on CXCR7. Methods: Eight-week-old male C57BL/6J mice were injected with DOX for consecutive 5 weeks, during which mice were treated with TC14012 twice a week. One week after the last dose injection, mice were euthanized after heart function examination. Markers of cardiac inflammation and fibrosis were evaluated. Cardiac RNA-seq was performed to explore the underlying molecular pathways. Key findings: TC14012 supplement significantly prevented DOX-induced cardiac systolic dysfunction, reflected by improved ejection fraction and fraction shortening, along with remarkable attenuation of DOX-induced cardiac perivascular and interstitial collagen deposition and neutrophils and macrophage infiltration. RNA-seq revealed that TC14012 prevention of DICT was accompanied with a remarkable stimulation of signals involving in cardiac contraction and energy reserve metabolic process, particularly glycogen and glucan metabolism that are crucial for meeting the cardiac energy demand in response to DOX induction. These signals could be further enriched into AMPK signaling pathway and validated by upregulation of AMPK phosphorylation. Besides, TC14012 prevention of DICT was accompanied with a significant reduction in cardiac mast cell activation and degranulation. These signals could be further enriched into Rap1 signaling pathway, and TC14012 was validated to inhibit Rap1 activity and mast cell activation. Most importantly, TC14012 treatment did not affect the suppressive effects of DOX on tumor growth in a syngeneic EL4 lymphoma-bearing, immunocompetent mouse model. Conclusions: We preliminary conclude that TC14012 prevents DICT by activating cardiac CXCR7 to reprogram cardiomyocyte metabolism and prevent cardiac damage and dysfunction via activating AMPK, and by antagonizing CXCR4 to inhibit cardiac mast cell infiltration and activation via blunting Rap1 activity but does not affect the anti-tumor activity of DOX.

PURPOSE Imlunestrant is a next-generation oral selective estrogen receptor (ER) degrader designed to deliver continuous ER target inhibition, including in ESR1- mutant breast cancer. This phase Ia/b trial determined the recommended phase II dose (RP2D), safety, pharmacokinetics, and efficacy of imlunestrant, as monotherapy and in combination with targeted therapy, in ER-positive (ER+) advanced breast cancer (ABC) and endometrial endometrioid cancer. The ER+/human epidermal growth factor receptor 2–negative (HER2–) ABC experience is reported here. METHODS An i3+3 dose-escalation design was used, followed by dose expansions of imlunestrant as monotherapy or in combination with abemaciclib with or without aromatase inhibitor (AI), everolimus, or alpelisib. Imlunestrant was administered orally once daily and with the combination partner per label. RESULTS Overall, 262 patients with ER+/HER2– ABC were treated (phase Ia, n = 74; phase Ib, n = 188). Among patients who received imlunestrant monotherapy (n = 114), no dose-limiting toxicities or discontinuations occurred. At the RP2D (400 mg once daily), patients (n = 51) reported grade 1-2 nausea (39.2%), fatigue (39.2%), and diarrhea (29.4%). Patients at RP2D had received previous cyclin-dependent kinase 4/6 inhibitor (CDK4/6i; 92.2%), fulvestrant (41.2%), and chemotherapy (29.4%) for ABC and achieved a median progression-free survival (mPFS) of 7.2 months (95% CI, 3.7 to 8.3). Among patients who received imlunestrant + abemaciclib (n = 42) and imlunestrant + abemaciclib + AI (n = 43), most (69.4%) were treatment-naïve for ABC; all were CDK4/6i-naïve. Patients treated with imlunestrant + everolimus (n = 42)/alpelisib (n = 21) had received previous CDK4/6i (100%), fulvestrant (34.9%), and chemotherapy (17.5%) for ABC. No new safety signals or interactions with partnered drugs were observed. The mPFS was 19.2 months (95% CI, 13.8 to not available) for imlunestrant + abemaciclib and was not reached for imlunestrant + abemaciclib + AI. The mPFS with imlunestrant + everolimus/alpelisib was 15.9 months (95% CI, 11.3 to 19.1)/9.2 months (95% CI, 3.7 to 11.1). Antitumor activity was evident regardless of ESR1 mutation status. CONCLUSION Imlunestrant, as monotherapy or in combination with targeted therapy, had a manageable safety profile with evidence of preliminary antitumor activity in ER+/HER2– ABC.

Abstract TET2 mutations (mTET2) are common genetic events in myeloid malignancies and clonal hematopoiesis. 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 these inflammatory circuits is unknown. To address this, we performed scRNA-seq and scATAC-seq in patients with COVID-19 with and without TET2-mutated clonal hematopoiesis reasoning that inflammation from COVID-19 may highlight critical downstream transcriptional targets of mTET2. Using this approach, we identified metastasis-associated lung adenoma transcript 1 (MALAT1), a therapeutically tractable lncRNA, as a central downstream effector of mTET2 that is both necessary and sufficient to induce the oncogenic proinflammatory 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 protein phosphatase 2A dephosphorylation, thus preventing resolution of inflammatory signaling. Significance: This work identifies MALAT1 as a requisite downstream effector of oncogenic feedforward inflammatory circuits necessary for the development of TET2-mutated CH and fulminant myeloid malignancy. We elucidate a novel mechanism by which MALAT1 “shields” p65 from dephosphorylation to potentiate this circuit and nominate MALAT1 inhibition as a future therapeutic strategy.

DDX41 -associated cytopenia(s)/myeloid neoplasms ( DDX41 -C/MNs) are an emerging pathologic entity. We examined the hematopathologic findings in DDX41 -C/MNs with both a germline and somatic DDX41 mutation ( DDX41 -C/MNs-GS). We reviewed the peripheral blood and bone marrow (BM) findings from treatment-naive patients with DDX41 -C/MNs-GS. Thirty cases were identified: 10% (3/30) were classified as clonal cytopenia(s) of unknown significance (CCUS), 17% (5/30) as myelodysplastic neoplasm/syndrome (MDS) with <5% blasts, 20% (6/30) as MDS with 5% to 9% blasts, 20% (6/30) as MDS with 10% to 19% blasts, and 33% (10/30) as acute myeloid leukemia (AML). All patients were cytopenic; circulating blasts were rare (23%, 7/30). 63% (19/30) showed dysmegakaryopoiesis. Dyserythropoiesis and dysgranulopoiesis were uncommon; seen in 20% (6/30) and 7% (2/30), respectively. Sixty-six percent (19/29) of cases were normocellular; 43% (13/30) showed erythroid predominance. Flow cytometry revealed an unremarkable blast myeloid phenotype. Blasts were intermediate sized with round nuclei, distinct nucleoli, and light blue cytoplasm with azurophilic granules. The karyotype was predominantly normal (93%, 26/28). All germline mutations were deleterious: 53% (16/30) truncating and 47% (14/30) missense. The most common somatic variant was the R525H mutation in 70% (21/30). The BM diagnostic spectrum in DDX41- C/MNs that harbor both a germline and somatic DDX41 mutation is broad—ranging from CCUS to AML. We describe consistent hematopathologic findings that pathologists may expect in these cases.

Abstract Background DNMT3A and TET2 are epigenetic regulator genes commonly mutated in age-related clonal hematopoiesis (CH). Despite having opposing epigenetic functions, these mutations are associated with increased all-cause mortality and a low risk for progression to hematological neoplasms. While individual impacts on the epigenome have been described using different model systems, the phenotypic complexity in humans remains to be elucidated. Results Here we make use of a natural inflammatory response occurring during coronavirus disease 2019 (COVID-19), to understand the association of these mutations with inflammatory morbidity and mortality. We demonstrate the age-independent, negative impact of DNMT3A mutant CH on COVID-19-related cytokine release severity and mortality. Using single cell proteogenomics we show that DNMT3A mutations involve myeloid and lymphoid cells. Using single cell multiomics sequencing, we identify cell-specific gene expression changes associated with DNMT3A mutations, along with significant epigenomic deregulation affecting enhancer accessibility, resulting in overexpression of IL32, a proinflammatory cytokine that can result in inflammasome activation in monocytes and macrophages. Finally, we show with single cell resolution that the loss of function of DNMT3A is directly associated with increased chromatin accessibility in mutant cells. Conclusions We demonstrate the negative prognostic impact of DNMT3Amt CH on COVID-19 related inflammatory morbidity and mortality. DNMT3Amt CH involves myeloid and lymphoid cells and in the context of COVID-19, was associated with inflammatory transcriptional priming, resulting in overexpression of IL32. This overexpression was secondary to increased chromatic accessibility, specific to DNMT3Amt CH cells. DNMT3Amt CH can serve as a potential biomarker for adverse inflammatory outcomes.

Abstract Background Delirium is a common complication of older people in hospitals, rehabilitation and long-term facilities. Objective To assess the worldwide use of validated delirium assessment tools and the presence of delirium management protocols. Design Secondary analysis of a worldwide one-day point prevalence study on World Delirium Awareness Day, 15 March 2023. Setting Cross-sectional online survey including hospitals, rehabilitation and long-term facilities. Methods Participating clinicians reported data on delirium, the presence of protocols, delirium assessments, delirium-awareness interventions, non-pharmacological and pharmacological interventions, and ward/unit-specific barriers. Results Data from 44 countries, 1664 wards/units and 36 048 patients were analysed. Validated delirium assessments were used in 66.7% (n = 1110) of wards/units, 18.6% (n = 310) used personal judgement or no assessment, and 10% (n = 166) used other assessment methods. A delirium management protocol was reported in 66.8% (n = 1094) of wards/units. The presence of protocols for delirium management varied across continents, ranging from 21.6% (on 21/97 wards/units) in Africa to 90.4% (235/260) in Australia, similar to the use of validated delirium assessments with 29.6% (29/98) in Africa to 93.5% (116/124) in North America. Wards/units with a delirium management protocol [n = 1094/1664, 66.8%] were more likely to use a validated delirium test than those without a protocol [odds ratio 6.97 (95% confidence interval 5.289–9.185)]. The presence of a delirium protocol increased the chances for valid delirium assessment and, likely, evidence-based interventions. Conclusion Wards/units that reported the presence of delirium management protocols had a higher probability of using validated delirium assessments tools to assess for delirium.

5589 Background: Imlunestrant is a next-generation oral SERD designed to deliver continuous estrogen receptor (ER) target inhibition aimed to improve outcomes for patients (pts) with ER+ cancers. In the first-in-human Phase 1a/1b EMBER trial (NCT04188548), imlunestrant showed favorable safety, pharmacokinetics, and clinical benefit in pre-treated pts with ER+ advanced breast cancer or EEC. Here, we report updated imlunestrant monotherapy data and the first clinical data of imlunestrant + abemaciclib in ER+ EEC pts from EMBER. Methods: Eligible pts had ER+ EEC previously treated with (or deemed inappropriate for) platinum-containing chemotherapy. Prior fulvestrant or aromatase inhibitor therapy was not allowed. In Phase 1a, pts received imlunestrant alone, and in Phase 1b, pts were randomized (1:1) to imlunestrant alone or with abemaciclib. Plasma samples were collected at baseline (all pts) and at cycle 2 (monotherapy pts) for ctDNA analysis (Guardant 360 assay) to correlate with clinical benefit. Primary endpoints were RP2D of imlunestrant monotherapy and in combination. Secondary endpoints included safety, tolerability, and overall response rate (ORR), clinical benefit rate (CBR: complete or partial response, or stable disease ≥24 weeks), and progression-free survival (PFS) using RECIST v1.1. Results: Overall, 72 pts were treated; 39 pts received monotherapy (33 at 400mg [RP2D] and 6 at 800mg po daily) and 33 pts received imlunestrant (29 at 400mg and 4 at 800mg po daily) + abemaciclib (150mg po twice daily). Baseline characteristics, safety, and preliminary efficacy are presented (Table). For monotherapy, the most common TEAEs (all grade/grade 3) were nausea (36%/3%), diarrhea (26%/0), urinary tract infection (26%/3%), and abdominal pain (21%/8%). For imlunestrant + abemaciclib, the most common TEAEs (all grade/grade 3) were diarrhea (88%/3%), nausea (67%/0), fatigue (49%/9%) and anemia (46%/12%). In the monotherapy arm, pts with deeper (≥ 50%) declines in ctDNA variant allele frequency had a higher CBR (4/7 vs 4/17). Conclusions: Imlunestrant, as monotherapy or with abemaciclib, appears safe and tolerable with preliminary evidence of efficacy in pts with metastatic ER+ EEC. Clinical trial information: NCT04188548 . [Table: see text]

1027 Background: Imlunestrant is a next-generation, oral SERD designed to deliver continuous ER-target inhibition. In the first-in-human Phase 1a/b EMBER study (NCT04188548), imlunestrant demonstrated favourable safety, PK, and clinical benefit when administered as monotherapy or with targeted therapy in ER+, HER2- aBC. Here we present clinical data of imlunestrant with HER2 targeted therapy, in patients (pts) with ER+, HER2+ aBC enrolled in EMBER. Methods: Pts were randomized to imlunestrant (400mg po daily) + trastuzumab (H), with or without (±) abemaciclib (Part C) or received maintenance treatment with imlunestrant + H + pertuzumab (P) (Part E), at standard doses in 21-day cycles. Key eligibility (Part C): ≥ 2 prior HER2 directed regimens, no prior CDK4/6i or fulvestrant; (Part E): received 1st line induction taxane chemotherapy (any duration) + H + P, without disease progression and ≤1 prior therapy for aBC. Key endpoints included safety, PK, ORR, CBR and PFS. Results: Overall, 45 pts with ER+/HER2+ aBC received the following combinations: imlunestrant + H (n=18), imlunestrant + H + abemaciclib (n=21; 1 pt received 800 mg imlunestrant), and imlunestrant + H + P (n=6). Baseline characteristics, safety, and preliminary efficacy are presented below (Table). Most TEAEs were grade 1-2. Common TEAEs with imlunestrant + H were fatigue (33%) and nausea (28%); with imlunestrant + H + abemaciclib were diarrhea (100%), neutropenia (57%), fatigue (52%) and nausea (48%); and with imlunestrant + H + P were diarrhea (50%) and arthralgia (50%). Imlunestrant PK was consistent with those previously reported with no drug-drug interactions observed with the combinations. From Part C, sequencing of baseline plasma ctDNA samples (n=37) identified prevalent mutations in TP53 (49%), PIK3CA (30%), ESR1 (24%), and GATA3 (14%). Clinical activity of imlunestrant in this ER+/HER2+ population, while based on small numbers, is promising. Conclusions: Imlunestrant in combination with trastuzumab ± abemaciclib or pertuzumab was well tolerated, showed no drug-drug interactions, and demonstrated preliminary antitumor activity in pts with ER+/HER2+ aBC. Clinical trial information: NCT04188548 . [Table: see text]