KPT-9274, a potentially first-in-class, dual NAMPT/PAK4 inhibitor, has shown single-agent anticancer activity in hematologic and solid tumor cell lines and xenografts. KPT-9274 has shown anti-tumor activity in combination with nivolumab in nonclinical models. KCP-9274-901 was a first-in-human, multi-center, open-label clinical study to assess preliminary safety, tolerability, and efficacy of KPT-9274 in patients with advanced solid tumors. This study was conducted in three parts. A two-part (A, B) dose escalation phase to determine the recommended phase II dose and maximum tolerated dose (MTD) of KPT-9274 alone and with niacin. Part 3 (C) was a dose-finding and expansion phase in patients with melanoma treated with KPT-9274 plus nivolumab. A total of 60 patients were enrolled (part A and B n = 50; part C n = 10). Three dose-limiting toxicities (DLTs) were observed in the 40-mg (n = 1) and 80-mg plus niacin (n = 2) cohorts. MTD was not reached in parts A and B and was 60 mg plus nivolumab in part C. The most frequently reported TEAEs (≥30 www.clinicaltrials.gov , NCT02702492.

Myeloid sarcoma, an aggressive extramedullary subtype of acute myeloid leukemia (AML), occurs in approximately 20% of patients and remains strikingly understudied in large-scale genomic and multiomic investigations. The key drivers of its tumor evolution are largely unknown; timely detection in asymptomatic patients poses a clinical challenge, and effective treatment options are limited, as patients are often excluded from clinical trials, rendering it a largely neglected disease entity. In this study, we demonstrate that myeloid sarcoma evolves from medullary AML but exhibits distinct site-specific clonal evolution. This is supported by unique transcriptional signatures of myeloid sarcoma, reflecting adaptation to the extramedullary microenvironment. We establish a proof of concept that circulating tumor DNA (ctDNA) sequencing captures the molecular composition of myeloid sarcoma, offering a potential noninvasive approach for molecular profiling of extramedullary AML. Our findings highlight marked differences between medullary AML and myeloid sarcoma, including universal molecular evolution and RAS pathway activation as disease hallmarks. SIGNIFICANCE:We provide a comprehensive multiomic characterization of myeloid sarcoma, identifying key molecular pathways that contribute to its development, and suggest ctDNA as a noninvasive method of detection. We identify RAS pathway activation and transcriptional adaptation to the solid tissue microenvironment as cardinal features of myeloid sarcoma, suggesting novel therapeutic avenues.

In a mouse model of FGFR1-driven leukemia, we demonstrated a role for circulating non-conventional monocyte-derived macrophages in the peripheral blood, which suppressed T-cell function and promoted leukemogenesis. A single cell RNA sequencing (scRNA-Seq) analysis of these leukemia-associated macrophages (LAMs) identified LAM-specific dysregulation of gene expression associated with leukemogenesis. Based on the top markers identified in these LAMs, we generated a LAM score based on the expression levels of a 32 gene signature. This scoring system was then applied to the transcriptomic data from a cohort of 838 newly diagnosed patients treated on Alliance/CALGB protocols, who were similarly treated with intensive cytarabine/daunorubicin-based chemotherapy on the CALGB/Alliance for the Clinical Trials in Oncology protocol. Patients were subclassified as those with high and low LAM scores. Patients with a high LAM score had shorter overall survival, disease-free survival and event-free survival compared to those with a low LAM score. We also noted a strong association of FLT3-ITD, RUNX1 and TP53 mutations with high LAM scores. Applying the LAM score to the current European Leukemia Network risk group criteria, independent prognostic implications and a refined prognostic significance of each subgroup were provided, indicating the value of including immune microenvironment data into AML risk stratification.

Mutations in the RAS/MAPK signaling pathway are recurrent in acute myeloid leukemia (AML), primarily involving NRAS and KRAS. In contrast, mutations in the gene encoding an effector protein, BRAF, occur at relatively lower frequencies in AML and are associated with poor outcomes. To date, no comprehensive analysis has assessed the clinical and molecular characteristics of BRAF-mutated AML. In this study, we report the identification of canonical and non-canonical BRAF mutations in ~1% of 5,779 consecutive clinically and molecularly fully-annotated AML patients treated at two major United States Cancer Centers (50/5779 AML patients: 21 newly diagnosed AML; 9 relapsed/refractory; 20 newly diagnosed secondary AML). We performed single-cell multiomic analysis on a subset of AML samples. BRAF mutations were enriched in myelodysplasia-related AML (AML-MR), and most mutations were located outside the V600 hotspot. Single-cell multiomic profiling delineated BRAF mutation class-specific patterns of co-mutations, clonality, and immunophenotypes. Notably, BRAF mutations and other signaling co-mutation(s) could be found in the same cell, a finding that significantly diverges from prior studies of RAS-mutant AML. In this cohort, BRAF-mutant AML patients had poor overall survival with currently available treatments, including venetoclax-based regimens. Drug sensitivity data suggest possible avenues for targeted treatment of BRAF-mutated AML.

This file contains four supplementary tables S1 - S4 and eight supplementary figures S1 - S8.

Abstract Introduction: AML is a molecularly heterogeneous disease that is classified by recurrent cytogenetic abnormalities and gene mutations. Recent studies have shown divergent frequencies of several genetic aberrations depending on genetic ancestry and self-reported race/ethnicity, highlighting the need to broaden sequencing efforts to include more diverse pts. Methods: We performed paired tumor/normal whole exome sequencing (WES) and transcriptome sequencing on 271 ancestry and/or ethnically diverse pts [including 100 African American (AA) and 71 self-identified Hispanic pts; CALGB/Alliance], and a validation cohort of 45 AA pts (University of Pennsylvania). Results: We identified >20 genes to be mutated in 3-8% of pts that were not seen in previous sequencing efforts of predominantly non-Hispanic White/European ancestry (EA) pts. Notably, variants in genes encoding Rho-GTPase regulatory proteins (ARHG family, belonging to the RAS gene superfamily) were identified in 12% of pts, placing these genes in the top 5 of recurrently mutated genes in this pt cohort. This frequency was confirmed in the second cohort of AA pts (n=7/45, 15%). In contrast, analysis of 805 EA adults with WES data (BeatAML 2022) and 877 pediatric AML pts (TARGET) found ARHG gene family variants in 26/805 (3%) and 17/877 (1.9%) of EA AML pts, respectively. With a median age of 41y, ARHG-mutated(m) pts tended to be younger (P=.16) and more often diagnosed with core-binding factor AML (39% vs 19%, P=.02). ARHG mutations frequently co-occurred with NRAS and FLT3 mut (each found in 35% of ARHGm pts). Notably, survival of ARHGm pts was poor, with a median overall survival (OS) of <12 months, thereby mirroring OS of the 2022 European LeukemiaNet (ELN) Adverse risk group. Within the 2022 ELN Favorable risk group in the ancestry diverse cohort, ARHGm pts had shorter OS than ARHGwt pts (P=.02). The clinical outcome was especially poor in young adolescents and adults (AYA, 18-39y) (mut vs wt; 3y disease-free survival, 10% vs 50%, P<.001; 3y OS, 20% vs 55%, P=.008). RNAseq of 17 ARHGm pts showed transcriptomic RAS pathway activation, with 52% displaying a RAS-associated signature, also in the absence of other RAS mutations. Furthermore, bulk transcriptomic analyses of 1250 AML pts identified 120 predicted RAS signature genes, with the upregulated genes being enriched in metallopeptidases, MAP kinase phosphatases, and ARHG genes. Conclusion: We identified mutations in ARHG family genes as frequent yet thus far unrecognized RAS pathway activators in AML associated with poor survival that are not yet included in clinical testing panels. Their lack of recognition is likely due to the heterogeneity of mutationally affected ARHG family genes, enrichment in AYA pts and the high frequency in pts of non-European ancestry, both of which are pt populations that were underrepresented in previous sequencing efforts. Citation Format: Ethan Hamp, Lorenz Oelschläger, Bailee N. Kain, Deedra Nicolet, Krzysztof Mrozek, Katherine E. Miller, Audrey Bollas, Michael C. Walker, Christopher J. Walker, Jill Buss, Andrea Laganson, Andrew J. Carroll, William G. Blum, Bayard L. Powell, Geoffrey L. Uy, Wendy Stock, Marina Y. Konopleva, Richard M. Stone, John C. Byrd, Martin Carroll, Tanmoy Sarkar, Akmaljon Salimov, Benjamin J. Kelly, Electra D. Paskett, Jesse J. Plascak, Shannon McWeeney, Jeffrey W. Tyner, Jeffery Klco, Nathan Salomonis, H. Leighton Grimes, Elaine R. Mardis, Ann-Kathrin Eisfeld. Novel Rho-GTPase regulatory protein gene family variants are frequent and associate with poor survival in patients (pts) with acute myeloid leukemia (AML) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 7897.

Myelofibrosis (MF) is a chronic myeloproliferative neoplasm (MPN) characterized by splenomegaly, constitutional symptoms, marrow fibrosis, cytopenias and inflammation. Janus kinase 2 (JAK2) inhibitors, such as ruxolitinib, reduce splenomegaly and alleviate symptoms but have limited disease-modifying activity, and resistance frequently develops. Selinexor, an oral selective exportin (XPO1) inhibitor, restores nuclear retention of tumour suppressors and inhibitors of inflammatory signalling. Dual XPO1/JAK2 inhibition targets complementary downstream pathways, enhancing suppression of MF progenitor cell fitness. We evaluated selinexor plus ruxolitinib in MF models, including JAK2V617F or calreticulin (CALR) exon 9-mutant MPN cell lines and samples from patients with MF. The combination showed greater anti-proliferative activity than JAK2 inhibition alone and suppressed colony formation from MF Cluster of Differentiation 34 (CD34)+ cells. Selinexor remained active in a ruxolitinib-resistant MPN cell line, inducing G1 arrest and apoptosis. Multi-omic analyses demonstrated increased nuclear retention of p53 and disruption of Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) signalling, complementing and extending ruxolitinib-targeted pathways. The combination suppressed NF-κB transcriptional activity and reduced Tumor Necrosis Factor alpha (TNFα), Interleukin-6 (IL-6) and Monocyte Chemoattractant Protein-1 (MCP-1) secretion from MF patient peripheral blood mononuclear cells. These findings highlight that selinexor plus ruxolitinib affects both MF haematopoietic cell-intrinsic and microenvironment-related pathways, providing a novel disease-modifying strategy with the potential to improve clinical outcomes in patients with MF.

OBJECTIVE:This study aimed to provide proof-of-concept that multi-receptor antagonist peptides can be generated by covalently linking independent antagonist peptides that block calcitonin gene-related peptide (CGRP8-37) or pituitary adenylate cyclase-activating peptide (PACAP)/vasoactive intestinal peptide (VIP) (PACAP6-38) activity. BACKGROUND:The neuropeptides CGRP and PACAP are implicated in migraine and pain pathogenesis. CGRP and PACAP are elevated during a migraine attack, and following infusion of either peptide, patients develop migraine-like attacks. This indicates that targeting both these systems may provide therapeutic benefits. Mechanistic studies suggest that these peptides largely act independently from one another. Therefore, blocking the activity of both CGRP and PACAP simultaneously could provide a clinical advantage over individual blockade. One strategy is to develop a single antagonist capable of inhibiting the signaling of both CGRP and PACAP receptors, a multi-receptor antagonist. N-terminal truncation of CGRP and PACAP generates the antagonists CGRP8-37 and PACAP6-38, respectively. These are commonly used as research tools for the CGRP and PACAP receptors. These peptide antagonists were, therefore, used as the basis for the design of multi-receptor antagonists against the CGRP and PACAP receptors and to test their functionality in vitro. METHODS:To generate multi-receptor antagonists, CGRP8-37 was linked through 1,3-dipolar cycloaddition using click chemistry to PACAP6-38 at amino acid residues 21, 34, or 38. The ability of these multi-receptor antagonists to block CGRP activity (CGRP and AMY1 receptors) and PACAP-38, PACAP-27, and VIP activity (PAC1, VPAC1, and VPAC2 receptors) was then characterized in transfected Cos7 cells. The peptides were then further examined in pain-relevant rat spinal cord cultures, as a model of endogenous receptors. RESULTS:Multi-receptor antagonists were successfully generated, displaying similar antagonist potency to their parental antagonists in both transfected Cos7 cells and in spinal cord cultures. Interestingly, CGRP8-37 linked to position 38 of PACAP6-38 was a more potent antagonist of CGRP activity than CGRP8-37. CONCLUSION:This study provides proof-of-concept evidence for the development of potent multi-receptor antagonists capable of blocking both CGRP and PACAP activity.

Introduction: Selinexor, a first-in-class oral selective XPO1 inhibitor, in combination with ruxolitinib in JAK inhibitor-naïve patients with myelofibrosis (MF) has shown rapid, deep, and sustained spleen and symptom responses with associated reductions in proinflammatory cytokines (Tantravahi et al., ASH 2023). In a JAK2V617F-driven mouse model, selinexor treatment selectively suppressed JAK2V617F+ progenitors compared to normal progenitors and decreased myeloproliferation, demonstrating disease-modifying potential (Yan et al., CCR 2019). In MF, dysregulation of the NF-κB pathway contributes to disease development and progression by activating proinflammatory cytokines that perturb the bone marrow niche and suppress normal hematopoiesis. Selinexor has been shown to inhibit NF-κB activity by preventing nuclear export of both p65 and IκB, which allows IκB to bind to p65 in the nucleus, repressing the NF-κB complex's transcriptional activity. High throughput imaging flow cytometry allows for high-content image analysis and has proven useful in determining subcellular location of proteins. Here we used imaging flow cytometry to monitor selinexor-induced changes in subcellular localization of proteins relevant to MF pathogenesis in the HEL cell line as a model of JAK2V617F MF, as well as MF patient CD34+ cells. Methods: Cells were incubated with 250 nM selinexor for 16 hours (IC50 at 72 hours=237 nM for HEL cells) followed by fixation with formaldehyde, permeabilization with methanol, then incubated overnight at 20°C with fluorescently-conjugated antibodies targeting various components of the NF-κB pathway, namely Transcription factor p65 (RELA), Transcription factor RelB (RELB), NF-κB inhibitor alpha (IkBα), proto-oncogene c-Rel (REL). Signals for CD45 and DAPI defined the boundaries of the cytoplasm and nucleus. Data was collected on a 4-laser, 2-camera ImageStream Mk II imaging flow cytometer. The similarity score, a derivative of linear regression with positive values noting correlated signal origin, was calculated by IDEAS v6.2 software for each cell and used to infer nuclear/cytoplasmic localization. Analysis was limited to cells in G0/G1 to ensure an intact nuclear envelope. The patient sample analyzed was from the bone marrow of a patient with MF secondary to polycythemia vera, at transformation to acute myeloid leukemia (70% atypical CD34+ myeloblasts, CD33-negative; fibrosis 3/3). Mutations detected in the bone marrow included JAK2V617F, SRSF2P95R, NRASG12S, TET2E155fs, TET2F1287S, and a newly emerged RUNX1D198N mutation. The patient was previously treated with ruxolitinib, fedratinib, and ilginatinib/NS018, with adverse events and lack of response. Results: Selinexor induced G0/G1 cell cycle arrest at 16 hours in HEL cells. Preliminary data showed that exposure of HEL cells to selinexor led to pronounced nuclear sequestration of several NF-κB family members. Cells with nuclear localization of RELA increased from 39.4% in DMSO-treated controls to 93.2% following selinexor treatment. IκBα translocation rose from 33.1% to 85.1%, consistent with the previously described mechanism of action for selinexor. Interestingly, RELB showed a marked nuclear increase from 48.0% to 98.4% which may be mechanistically important as emerging evidence (Navarro et al., Cell Discovery 2025) points to its potential for tempering RELA-driven pro-inflammatory signaling through competition for DNA binding or direct complex formation. IKKα/β showed a modest decrease in nuclear localization from 95.1% to 89.2%, while REL localization remained largely unchanged. Similar trends were observed in a preliminary analysis of primary CD34⁺ cells, including IKBa and RELB. Additional markers are being evaluated, and experimentation is ongoing. Conclusions Selinexor treatment of MPN cells resulted in nuclear accumulation of both p65 (total and phosphorylated) and IkBα, consistent with selinexor's mechanism of suppressing NF-kB activity through nuclear sequestration of p65 and IkB. These events occur in G0/G1 phase cells prior to apoptosis, indicating that nuclear sequestration may impede continued proliferation and survival. We are evaluating multiple additional primary MF CD34+ patient samples and results will be presented. Selinexor is currently being evaluated in the SENTRY (XPORT-MF-034) phase 3 clinical trial (NCT04562389) in combination with ruxolitinib for JAK inhibitor naïve patients.

The influence of the nervous system on the intestine is carried out by a combination of enteric, sensory, and autonomic innervation. However, disambiguating the functions of these physiologically distinct intestine-innervating neuronal populations has been a challenge. Here, we develop a collection of mouse genetic tools that enable precise manipulation and examination of intestine-innervating neurons, particularly those in the enteric nervous system, which represent the most frequent of the intestine-innervation neural populations. We report that an array of transcriptionally distinct enteric neuron subpopulations has distinct morphological specializations and influences on intestinal function, including controlling fecal output, fecal hydration, and food intake. We also report that subpopulations within the enteric nervous system require extrinsic innervation to exert control over intestinal transit or food intake. Collectively, these genetic approaches enable interrogation of the enteric nervous system and further study of its interactions with broader neural networks in the body.

Several therapeutic agents have been approved for treating multiple myeloma, a cancer of bone marrow-resident plasma cells. Predictive biomarkers for drug response could help guide clinical strategies to optimize outcomes. In this study, we present an integrated functional genomic analysis of tumor samples from patients multiple myeloma that were assessed for their ex vivo drug sensitivity to 37 drugs, clinical variables, cytogenetics, mutational profiles, and transcriptomes. This analysis revealed a multiple myeloma transcriptomic topology that generates "footprints" in association with ex vivo drug sensitivity that have both predictive and mechanistic applications. Validation of the transcriptomic footprints for the anti-CD38 mAb daratumumab (DARA) and the nuclear export inhibitor selinexor (SELI) demonstrated that these footprints can accurately classify clinical responses. The analysis further revealed that DARA and SELI have anticorrelated mechanisms of resistance, and treatment with a SELI-based regimen immediately after a DARA-containing regimen was associated with improved survival in three independent clinical trials, supporting an evolutionary-based strategy involving sequential therapy. These findings suggest that this unique repository and computational framework can be leveraged to inform underlying biology and to identify therapeutic strategies to improve treatment of multiple myeloma. Significance: Functional genomic analysis of primary multiple myeloma samples elucidated predictive biomarkers for drugs and molecular pathways mediating therapeutic response, which revealed a rationale for sequential therapy to maximize patient outcomes.

Importance:Therapeutic responses in acute myeloid leukemia (AML) demonstrate considerable variability both across and within established risk stratifications and age groups. Moreover, significant racial disparities persist, with Black patients experiencing inferior survival outcomes compared with their White counterparts. Objective:To validate the association of the previously reported 10 single nucleotide variant (SNV)-based ara-C pharmacogenomics score (ACS10) with survival outcomes in a large cohort of pediatric AML patients; to evaluate whether ACS10 remains relevant in an adolescent and young adult (AYA) population of patients with AML treated with similar intensive induction chemotherapy protocols; and to assess the association of ACS10 with race and treatment outcomes in both cohorts. Design, Setting, and Participants:This cohort study included patients from the Children's Oncology Group's AAML1031 trial, a multicenter, open-label randomized clinical trial that enrolled pediatric patients with newly diagnosed, treatment-naive primary AML from June 2011 to July 2017 (aged 0 to 29.5 years) and from the Alliance for Clinical Trials in Oncology frontline protocols, which included AYA patients from 9 different trials that enrolled patients with newly diagnosed AML from 1992 to 2010. Data were analyzed from September 2022 to March 2025. Exposures:Patients in the AAML1031 trial were randomized to 2 arms, standard chemotherapy alone or standard chemotherapy with the addition of bortezomib. Patients in the Alliance for Clinical Trials in Oncology cohorts were treated with similar intensive induction chemotherapy protocols. Main Outcomes and Measures:ACS10 scores were evaluated for association with outcomes according to race, treatment arm, and hematopoietic stem cell transplant (HSCT) status. Results:The study included 1086 patients with AML. There were 717 patients from the pediatric AML cohort (median [range] age, 9.6 [0.04-29.2 years]; 379 [53%] male; 33 [5%] Asian, 84 [12%] Black, and 522 [73%] White) and 369 AYA patients with AML from the Alliance for Clinical Trials in Oncology group (median [range] age, 30 [17-39] years; 196 [53%] male; 7 [2%] Asian, 32 [9%] Black, and 288 [78%] White). Within the standard treatment arm of AAML1031, patients in the low ACS10 group had significantly worse event-free survival (EFS) compared with those in the high ACS10 group (all patients: hazard ratio [HR], 1.42; 95% CI, 1.05-1.95; P = .02; non-HSCT cohort: HR, 1.48; 95% CI, 1.06-2.07; P = .02). The ACS10 score remained significantly associated with EFS in multivariable analysis after adjusting for age, race, risk group and white blood cell count, within the standard treatment arm (HR, 1.44; 95% CI, 1.03-2.02; P = .03). In the Alliance for Clinical Trials in Oncology AYA non-HSCT cohort, the low ACS10 score group had significantly inferior overall survival (OS) and a higher point estimate for EFS compared with patients with a high ACS10 score (OS: HR, 1.50; 95% CI, 1.05-2.14; P = .03; EFS: HR, 1.32; 95% CI, 0.95-1.83; P = .10). A higher number of early deaths was observed in the low ACS10 group compared with the high ACS10 group, but the difference was not statistically significant (death within 30 days of treatment initiation: 6 of 112 [5%] vs 2 of 257 [1%]; P = .07). Across both cohorts, a low ACS10 score was significantly more abundant in Black patients compared with White patients (eg, in Alliance for Clinical Trials in Oncology cohort, 27 of 32 Black patients [84%] had low ACS10 scores compared with 64 of 288 White patients [22%]; P < .001) and inferior survival was observed in Black patients (eg, OS of Black compared with White patients in AAML1031 cohort: HR, 1.47; 95% CI, 1.02-2.13; P = .04). In the AAML1031 cohort, there were no significant differences in EFS or OS between Black and White patients receiving augmented treatment, suggesting that the addition of bortezomib was associated with benefit for Black patients. Conclusions and Relevance:In this study of 717 pediatric and 369 AYA patients with AML, the ACS10 score was associated with EFS in pediatric and AYA patients when treated with a standard induction regimen. There was a higher abundance of low ACS10 scores in Black patients, and Black patients treated with augmented therapy (ie, the addition of bortezomib) seemed to have improved outcomes. Integrating the ACS10 score into a prospective clinical trial to personalize induction therapy based on an individual's genetic profile has the potential to improve treatment outcomes.

Exportin-1 (XPO1) is a nuclear export protein that, when overexpressed, can facilitate cancer cell proliferation and survival and is frequently overexpressed or mutated in cancer patients. As such, selective inhibitors of XPO1 (XPO1i) function have been developed to inhibit cancer cell proliferation and induce apoptosis. This review outlines the evidence for the immunomodulatory properties of XPO1 inhibition and discusses the potential for combining and sequencing XPO1i with immunotherapy to improve the treatment of patients with cancer. Selinexor is a first-in-class XPO1i that is FDA-approved for the treatment of patients with relapsed and refractory (RR) multiple myeloma and RR diffuse large B cell lymphoma. In addition to the cancer cell intrinsic pro-apoptotic activity, increasing evidence suggests that XPO1 inhibition has immunomodulatory properties. In this review, we describe how XPO1i can lead to a skewing of macrophage polarisation, inhibition of neutrophil extracellular traps, modulation of immune checkpoint expression, blockade of myeloid-derived suppressor cells (MDSCs) and sensitisation of cancer cells to T cell and NK (natural killer) cell immunosurveillance. As such, there is an opportunity for selinexor to enhance immunotherapy efficacy and thus a need for clinical trials assessing selinexor in combination with immunotherapies such as immune checkpoint inhibitors, direct targeting monoclonal antibodies, chimeric antigen receptor (CAR)-T cells and cereblon E3 ligase modulators (CELMoDs).

INTRODUCTION:Tumor protein 53 gene (TP53) is the most frequently mutated gene in human cancers. TP53 mutation status may have prognostic value across malignancy types, and its use as a predictive biomarker is limited. Selinexor is a novel oral exportin 1 (XPO1) inhibitor with preliminary efficacy data as a maintenance treatment in advanced/recurrent TP53 wild-type (wt) endometrial cancer (EC), suggesting TP53wt may be a predictive biomarker for this therapy. XPO1 mediates nuclear to cytoplasmic trafficking of transcriptionally active p53, where it is degraded and rendered functionally inactive. Selinexor prevents this export to restore nuclear p53 and increase the transcription of p53 activated target genes. AREAS COVERED:This review examines the mechanism of action of selinexor related to p53, contextualizes the effectiveness of selinexor among EC subtypes within the context of the evolving diagnostic, predictive, and therapeutic landscape for treatment, and presents the relevant clinical studies for selinexor dose for its use in gynecological malignancies. Literature review was conducted on the PubMed database. EXPERT OPINION:The promising efficacy signal suggests selinexor has potential as a maintenance therapy for TP53wt EC to address current treatment gaps. A phase 3 study is currently enrolling to further evaluate its role in patients with advanced/recurrent EC.

Introduction: Selinexor (SEL) is an oral selective inhibitor of the nuclear export protein exportin 1 (XPO1). In combination with ruxolitinib (RUX), SEL has shown rapid, deep, and sustained spleen and symptom responses including disease modifying potential in patients with JAK inhibitor (JAKi)–naïve myelofibrosis (MF), with associated reductions in proinflammatory cytokines (Tantravahi SK, et al. Blood. 2023;142(suppl 1):622). MF is characterized by elevated levels of pro-inflammatory cytokines, which correlate with disease severity. Many of these cytokines, including IL-6 and TNFα, are transcriptionally regulated by NF-κB and activate the JAK/STAT signaling pathway. JAKis used in MF therapy, including RUX, momelotinib (MOM), and pacritinib (PAC), have limited impact on cytokine modulation. SEL inhibits NF-κB activity by preventing nuclear export of its inhibitor IκB. We hypothesize that SEL may attenuate cytokine release in MF by targeting NF-κB signaling, and its combination with JAKi may enhance therapeutic benefit. Methods: NF-κB transcriptional activity was assessed in TNFα-stimulated UKE1 (JAK2-V617F, TP53wt) and ELF-153 (JAK2/CALR/MPL wt and TP53-I251N) cells treated with SEL (250 nM) alone or in combination with JAKi (100 nM). Ex vivo analyses were conducted using viably frozen peripheral blood mononuclear cells (PBMCs) from pretreatment samples of seven patients with JAKi-naïve MF who were being evaluated for participation in the Phase 3 SENTRY trial (NCT04562389). Cells were stimulated with the TLR8 agonist R848 (0.5 µg/mL) to induce cytokine production and incubated for 24 hours with single-agent or combination treatments. Supernatants were collected, and IL-6 and TNFα levels were quantified using immunoassays. Results: SEL significantly reduced NF-κB activity in UKE1 and ELF-153 cells regardless of JAK2 or TP53 mutation status. In contrast, JAKi alone had varied, but minimal, effect on NF-κB transcriptional activity based on their different target profiles. SEL-mediated NF-κB inhibition was maintained in combination with JAKi. We investigated how the ex vivo treatment of PBMCs obtained from patients with MF could affect the production of pro-inflammatory cytokines. The molecular characteristics of the patients included bone marrow fibrosis grade (MF-2: 2/7, MF-3: 2/7, N/A: 3/7), driver mutation (JAK2: 4/7, CALR: 2/7, N/A: 1/7), and high–molecular risk (HMR) mutations (6/7). R848 stimulation of primary MF PBMCs led to a 30.5 ± 44–fold and 2.5 ± 0.8–fold increase in IL-6 and TNFα secretion, respectively, compared with unstimulated control. Single-agent SEL (100–500 nM) inhibited IL-6 secretion (range: -8.7% to -37.9%) in a dose-dependent manner compared to DMSO control. SEL had the highest single-agent activity of the tested compounds and reduced IL-6 levels by -22.1 ± 23.4%. Comparatively, RUX (+7.9 ± 15.7%), MOM (-2.3 ± 24.4%), and PAC (+2.1 ± 15.9%) alone had negligible effects. In combination with JAKi, SEL improved or maintained the inhibition of IL-6 production with RUX (-21.4 ± 27.5%), MOM (-26.4 ± 27.3%), and PAC (-30.4 ± 20.8%). Additionally, TNFα secretion was evaluated in 3 patients and SEL alone again showed the highest inhibition (-30 ± 33.5%) compared to JAKi [RUX (-4.5 ± 30.6%), MOM (-14.2 ± 13.3%), PAC (+14 ± 26.8%)]. The combination of SEL with RUX (-26.9 ± 47.1%) and MOM (-17.3 ± 22.3%) showed sustained TNFα inhibition, while combination with PAC showed moderate inhibition (-3.2 ± 16.9%). Interestingly for a high–molecular risk TP53mut patient, neither single–agent nor combination treatment showed IL-6 or TNFα suppression, though this phenomenon warrants further evaluation in follow–up studies. Notably, cytokine suppression was limited in patients with baseline IL-6 levels near the normal range. Cells from additional patients with MF are being evaluated and will be included in the presentation. Conclusion: XPO1 inhibition is a potentially fundamental mechanism that addresses key inflammatory and pathobiological features of MF. Here we demonstrate that SEL effectively suppresses ex vivo NF-κB–regulated pro-inflammatory cytokine production in PBMCs derived from patients with MF, both as a single agent and in combination with JAKi, further validating the potential of disease modification. The combinatory activity of XPO1 inhibition and JAK/STAT inhibitors supports the clinical use of SEL plus RUX in JAKi-naïve MF, which is being evaluated in the ongoing Phase 3 SENTRY trial (NCT04562389).

Mutations and deletions in TP53 are associated with adverse outcomes in patients with myeloid malignancies, and there is an urgent need for the development of improved therapies for TP53-mutant leukemias. Here, we identified mutations in TET2 as the most common co-occurring mutation in patients with TP53-mutant acute myeloid leukemia (AML). In mice, combined hematopoietic-specific deletion of TET2 and TP53 resulted in enhanced self-renewal compared with deletion of either gene alone. Tp53/Tet2 double-KO mice developed serially transplantable AML. Both mice and patients with AML with combined TET2/TP53 alterations upregulated innate immune signaling in malignant granulocyte-monocyte progenitors, which had leukemia-initiating capacity. A20 governs the leukemic maintenance by triggering aberrant noncanonical NF-κB signaling. Mice with Tp53/Tet2 loss had expansion of monocytic myeloid-derived suppressor cells (MDSCs), which impaired T cell proliferation and activation. Moreover, mice and patients with AML with combined TP53/TET2 alterations displayed increased expression of the TIGIT ligand, CD155, on malignant cells. TIGIT-blocking antibodies augmented NK cell-mediated killing of Tp53/Tet2 double-mutant AML cells, reduced leukemic burden, and prolonged survival in Tp53/Tet2 double-KO mice. These findings describe a leukemia-promoting link between TET2 and TP53 mutations and highlight therapeutic strategies to overcome the immunosuppressive bone marrow environment in this adverse subtype of AML.

The outcome of patients with acute myeloid leukemia (AML) worsens with increasing age. Dichotomization into “younger” and “older” patients is clinically routine and often dictates treatment options. We aimed to delineate whether molecular genetic features and/or outcome measures support assorting patient populations by age, including division into “younger” and “older” groups. We analyzed 2823 adult AML patients enrolled onto frontline chemotherapy-based clinical protocols of two cooperative study groups from USA and Germany who were profiled molecularly via targeted sequencing platforms. Frequencies of gene mutations and cytogenetic findings were depicted in 5-year age increments. Clinical outcomes of 2756 AML patients were analyzed with respect to molecular features, genetic-risk groups and age. Age-associated distributions of gene mutations and cytogenetic abnormalities were similar in both cohorts. There was almost linear shortening of overall survival with increasing age among all patients (P < 0.001) and within 2022 European LeukemiaNet-defined genetic-risk groups, with survival decreasing as age increased (favorable-risk, P < 0.001; intermediate-risk, P < 0.001; adverse-risk, P < 0.001). Although mutational profiles and outcomes of the youngest patients differed from those of older patients, there was no age cut-off identifying “younger” and “older” patients. These findings support more age-associated flexibility for drug approval and trial eligibility.