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Background: Despite the development and approval of effective therapies for multiple myeloma (MM), MM remains an incurable disease. Moreover, patients with high-risk cytogenetics, like translocation t(4;14), continue to have a poor prognosis compared to standard-risk patients. No novel agents have been approved specifically for this population. There remains an unmet need for precision therapies for MM that can target specific drivers of high-risk MM like t(4;14). Multiple myeloma SET domain-containing protein (MMSET) overexpression observed in 100% of patients with t(4;14) acts through the MMSET-H3K36me2 axis, which promotes malignant transformation through regulation of multiple oncogenic programs. KTX-1001, a methyl transferase inhibitor, is a novel, first-in-class, potent, oral, small molecule that inhibits MMSET and the methylation of lysine K36. KTX-1001 had favorable drug-like properties, demonstrated in vivo activity, and was well tolerated in non-clinical studies. Based on these data, KTX-1001 is now being studied in a Phase 1 dose escalation and expansion study in relapsed and refractory multiple myeloma (RRMM). Study Design and Methods: This multi-country, Phase 1, open-label study (NCT05651932) is designed to assess the safety, tolerability, and initial clinical activity of KTX-1001. The study will also examine the recommended phase 2 dose (RP2D), pharmacokinetics (PK) and pharmacodynamics (PD). Part A of this trial includes an accelerated titration, followed by 3+3 dose escalation with backfill of cohorts for dose optimization prior to moving to Part B, which is an expansion phase at the RP2D (please see Figure 1 for study design schematic). The expansion phase will only include patients with t(4;14). KTX-1001 will be administered orally daily and given until disease progression, unacceptable toxicity, or withdrawal from the study. Estimated enrollment for Parts A and B will be approximately 60 patients. The study will enroll patients with RRMM who have received ≥3 prior lines of therapy, including a proteasome inhibitor (PI), immunomodulatory drug (IMiD), and anti-CD38 antibody. Patients must have measurable disease, be ≥18 years of age, have an Eastern Cooperative Oncology Group score of ≤2, and adequate bone marrow, liver, and kidney function. Key exclusion criteria include history of or current plasma cell leukemia, active central nervous system (CNS) disease, or active unstable cardiovascular function. The primary endpoints of safety and tolerability include incidence of dose-limiting toxicity (DLTs), treatment-emergent adverse events (AEs), and treatment-related AEs. Secondary endpoints include plasma concentrations of KTX-1001 and efficacy outcomes such as objective response rate (ORR), duration of response (DOR), progression-free survival (PFS), and overall survival (OS). Exploratory biomarker and pharmacodynamic assessments will also be performed. The sample size was not determined by formal statistical methods but will be sufficient to provide preliminary information on safety, PK, PD, and efficacy. Statistical analyses will be primarily descriptive. Conclusion: This Phase 1 study will evaluate a potential treatment for RRMM utilizing KTX-1001, which is a novel, first-in-class, potent, oral small-molecule MMSET inhibitor. The study is open and actively enrolling patients at centers in the United States, Spain, France, and Canada.

Introduction Indolent systemic mastocytosis (ISM) is a rare clonal mast cell disease driven by the KIT D816V mutation in nearly all patients. Patients with ISM can present with debilitating acute and chronic cutaneous, gastrointestinal, neurocognitive, and systemic symptoms caused by the release of inflammatory mediators from abnormal mast cells. In some patients, symptoms are not adequately controlled with best supportive care (BSC) medications. Elenestinib (BLU-263) is a novel, investigational, oral, next-generation tyrosine kinase inhibitor that potently and selectively inhibits KIT D816V with limited central nervous system penetration and pharmacokinetics (PK) that support once daily dosing. HARBOR (NCT04910685) is a randomized, double-blind, placebo-controlled, phase 2/3 study assessing efficacy and safety of elenestinib in patients with ISM. Methods Eligible adult patients with ISM, confirmed following central review of bone marrow (BM) pathology, clinical, and laboratory findings per World Health Organization criteria and a moderate-to-severe symptom score based on minimum mean total symptom score (TSS) of the ISM-Symptom Assessment Form (ISM-SAF©2018), were stratified by baseline serum tryptase (<20 ng/mL vs ≥20 ng/mL) and randomly assigned 3:1 to elenestinib 25 mg, 50 mg, or 100 mg once daily + BSC (“elenestinib”) or placebo + BSC (“placebo”). The primary objective of Part 1 was to determine the recommended dose based on safety, PK, and pharmacodynamics. Secondary endpoints included changes in biomarkers of disease burden (serum tryptase, KIT D816V variant allele fraction [VAF], and BM mast cells) and ISM-SAF TSS. Three additional open-label PK groups enrolled patients at 50 mg, 75 mg, and 100 mg to further characterize PK and safety. Results As of data cutoff on July 3, 2023, a total of 122 patients with ISM have received their assigned treatment in Part 1 of the study; 39 were blinded and randomized to elenestinib or placebo, and 83 were treated with open-label elenestinib in the PK groups (21 patients at 50 mg, 34 patients at 75 mg, and 28 patients at 100 mg). Baseline demographics were similar to those reported for the general ISM population. After 12 weeks of therapy, symptom improvement was observed for all dose cohorts, and symptom reduction by TSS was greater for patients on elenestinib versus placebo in the blinded portion of Part 1. Patients receiving elenestinib at 25 mg, 50 mg, and 100 mg doses showed reduction (mean percent) from baseline for tryptase (-15.4%, -50.9%, and -68.4% vs 3.3%, respectively) and KIT D816VVAF (-37.5%, -70.3%, and -77.0% vs -2.5%, respectively) as compared to placebo. Similar reductions in TSS and disease-related biomarkers were observed in the open-label PK cohorts. After a median treatment duration of 35.3 weeks, elenestinib was well-tolerated at all dose levels. There were no treatment-related serious adverse events and no treatment-related adverse events that led to drug discontinuation. Conclusion Elenestinib at all tested doses demonstrated beneficial effects on disease-related symptoms and biomarkers of mast cell burden in this large and maturing cohort of patients with ISM with a moderate-to-severe symptom burden. Elenestinib was well tolerated across all dose levels with a promising early benefit-risk profile in ISM. These preliminary findings will inform dosing for the planned Part 2 of HARBOR, which will examine elenestinib versus placebo in a randomized, blinded, placebo-controlled setting.

Background: Goals of patient-centered care for management of relapsed or refractory follicular lymphoma (R/R FL) are to improve clinical outcomes while maintaining or improving health-related quality of life (HRQoL). In ELM-2 (NCT03888105), a Phase 2, open-label, multicohort, multicenter study, odronextamab monotherapy demonstrated high and durable complete response rates and generally manageable safety in patients with R/R FL. We report here, for the first time, patient-reported outcome (PRO) results from ELM-2 in patients with R/R FL. Methods: Patients with R/R FL Grade 1-3a received odronextamab IV at 80 mg weekly in 21-day cycles in Cycles (C) 1-4. Optimization of the step-up regimen to mitigate cytokine release syndrome (CRS) was reported previously. Odronextamab was administered with steroid prophylaxis and step-up doses of 0.7/4/20 mg in C1, then 80 mg on Days 1, 8, and 15 of C2-4. After C4, odronextamab maintenance continued at 160 mg every 2 weeks until disease progression or unacceptable toxicity. Patients with durable complete response (≥9 months) switched to dosing every 4 weeks. Patients completed EORTC QLQ-C30, FACT-Lym, and EQ-5D-3L questionnaires at Weeks 1 (baseline), 2, 3, 4, and 10, then every 8 weeks for the remainder of the first year and every 12 weeks in the second year. Results here focus on six key PRO scales: EORTC QLQ-C30 Global Health Status/Quality of Life (GHS/QOL), physical functioning (PF), role functioning (RF), and fatigue; FACT-Lym lymphoma subscale (LymS); and EQ-5D-3L visual analog score (VAS). Longitudinal analyses using mixed models for repeated measures (MMRM) were conducted through Week 50 (the last visit with ≥10 patients with PRO data). Changes from baseline were considered statistically significant if the 95% confidence interval did not contain zero. No adjustment for multiplicity was performed, hence all statistical significance is nominal. Published ranges for minimum important difference (MID) to define clinically meaningful changes are: EORTC QLQ-C30 scales, 10 points; FACT-Lym LymS, 2.9-5.4 points; and EQ-5D-3L VAS, 7-12 points. For responder and time to definitive deterioration (TTDD) analyses, the upper end of these published MID ranges was used to define deterioration or improvement. Results: At the ELM-2 interim data cutoff on 31-Jan-2023, 140 patients with R/R FL Grade 1-3a had received at least 1 dose of odronextamab. Median age was 60.5 years (range: 22-84), with 38.6% ≥65 years, 52.9% male, 57.1% White, 32.1% Asian, 52.2% ECOG=0, and 47.1% ECOG=1. Median duration of follow-up was 26.6 months (range: 6.2-37.5). PRO completion rates for EORTC-QLQ-C30, FACT-Lym, and EQ-5D-3L were high at baseline and remained high for all assessments through Week 50. At baseline, moderate levels of general health (GHS/QoL) and high levels of functioning (PF and RF) were observed that were higher (better) than reference values for general cancer or non-Hodgkin's Lymphoma (NHL). Fatigue scores at baseline were lower (less symptoms) than reference values for general cancer or NHL. EORTC QLQ-C30 GHS/QOL, PF, RF, and fatigue scores were maintained from baseline through Week 50 (Table). For EQ-5D-3L VAS, the overall estimated mean changes from baseline improved statistically significantly but did not reach MID thresholds (Table). For FACT-Lym LymS, overall estimated mean change from baseline statistically significantly improved, and scores improved statistically significantly from Weeks 10 to 42 (except Week 34), with clinically meaningful improvements at Weeks 26 and 42 (Figure). The proportion of patients reporting meaningful improvement or stability across the six scales was higher than the proportion reporting meaningful worsening through Week 50 (Table). The median TTDD for EORTC-QLQ-C30 GHS/QoL was 22.41 (95% CI: 14.59 to not yet reached) months, corresponding to the median PFS. Median TTDD was not reached for EORTC QLQ-C30 PF, FACT-Lym LymS, and EQ-5D-3L VAS scales. Conclusions: For patients with R/R FL, patient-reported HRQoL results were favorable during odronextamab treatment until disease progression, with no detriments on patient-reported symptoms, functioning, and overall quality of life. These results complement encouraging clinical efficacy, durability of responses, and tolerability observed in this highly refractory patient population and support the future role of odronextamab in the management of patients with R/R FL.

AbstractBackground and ObjectivesThere is limited research on management of metastatic anal canal squamous cell carcinoma (SCC) to the liver. This study aimed to describe outcomes for patients undergoing liver resection of anal SCC metastases.MethodsA multicenter, retrospective cohort study was conducted by three tertiary‐referral centers. Patients undergoing liver surgery between 2008 and 2022 were included. Cox regression analysis was performed to evaluate predictors of recurrence and survival and Kaplan–Meier analysis was performed for 1‐, 3‐, and 5‐year survival.ResultsTwenty‐one patients underwent liver resection and/or ablation. None were HIV positive and 24% had known HPV infection. 20/21(95%) patients had undergone Nigro protocol for management of the primary tumor with 12/21 (57%) patients experiencing complete response. 4/21 (19%) patients had synchronous liver metastases at time of diagnosis. Median tumor size was 5.0 cm and median tumor number was one. At analysis, 52% remained alive. Median overall survival was 32.2 months. 5‐year overall survival was 50%. Median recurrence‐free survival was 7.7 months and 5‐year recurrence‐free survival was 30%. Need for salvage abdominoperineal resection was negatively associated with recurrence‐free survival. The most common site of recurrence was the liver.ConclusionsLiver resection for metastatic anal SCC can be beneficial for appropriately selected patients.

Abstract Background Patent foramen ovale (PFO) can be identified in about 20-25% of the adult population and may result in variable degrees of left-to-right and right-to-left intracardiac shunting. The association between PFO and pyogenic brain abscess remains poorly understood. The current study aimed to compare the clinical characteristics and outcomes of pyogenic brain abscess in patients with and without PFO. Methods All adults with pyogenic brain abscess seen at Mayo Clinic from 1/1/2009-12/31/2021 who underwent either transesophageal echocardiography (TEE) or transthoracic echocardiography (TTE) with agitated saline shunt (bubble) study were included. Results A total of 222 patients developed pyogenic brain abscess during the study period; 148 (66.7%) patients were excluded due to unknown PFO status. Among 74 remaining patients, PFO was detected in 30 (40.5%) patients; 25 by TEE and 5 by TTE with bubble study (Figure 1). The prevalence of cryptogenic brain abscess (unable to identify the source of abscess) was significantly higher in patients with PFO as compared to those without PFO (53.3% versus 18.2%, p=0.002). Patients with PFO had a larger abscess size (25 mm [IQR 15.8-37.5] versus 15.5 mm [IQR 10.0-28.0], p=0.038). However, multiple abscesses were more common in the group without PFO (43.2% versus 20.0%, p=0.038). Additionally, patients with PFO had less documented bloodstream infection. There were no differences between other clinical characteristics and one-year, all-cause mortality between two groups. Conclusion These findings provide critical insights into the likely association between PFO and cryptogenic brain abscess; additional investigation is warranted. Disclosures Larry M. Baddour, MD, Boston Scientific: Advisor/Consultant|Roivant Sciences: Advisor/Consultant

Validated nonbiopsy methods to assure duodenal mucosal healing in celiac disease are lacking, yet ongoing mucosal injury is associated with anemia, osteoporosis, and lymphoma. Most providers utilize clinical data as surrogates of mucosal status to avoid additional esophagogastroduodenoscopy. The reliability of such surrogates to predict mucosal recovery has been incompletely evaluated. The aim of this study was to rigorously assess patterns of histologic mucosal recovery at follow-up in celiac disease and to correlate findings with clinical data. Gastrointestinal pathologists from 13 centers evaluated initial and follow-up duodenal biopsies from 181 celiac disease patients. Marsh scores and intraepithelial lymphocytes (IELs)/100 enterocytes were assessed blindly. Histology at follow-up was correlated with symptoms, immunoglobulin A anti–tissue transglutaminase titers and gluten-free diet adherence. Fifty-six/181 (31%) patients had persistent villous blunting and 46/181 (25%) patients had just persistently elevated IELs at follow-up, with only 79/181 (44%) patients having complete histologic remission. IEL normalization (82/181; 45%) lagged villous recovery (125/181;69%). In a minority of patients, villous blunting was limited to proximal duodenal biopsies. No correlation was found between Marsh scores and symptoms, normalization of immunoglobulin A anti–tissue transglutaminase serology, or diet adherence. Children showed greater recovery of Marsh score (P<0.001) and IELs (P<0.01) than adults. Persistent mucosal injury is common in celiac disease, with discordant villous/IEL normalization. Pathologist awareness of expected findings in celiac disease follow-up biopsies, including their frequent lack of correlation with clinical data, is important for patient management, and has implications for eligibility criteria for therapeutics currently in development.

Abstract Background Atrial fibrillation (AF) occurs more frequently in men, but women suffer more AF recurrence; mechanisms are not completely understood. Purpose To explore whether sex related differences in LA stiffness (LAstiffn) in patients with AF ablation could potentially explain differences in AF recurrence. Methods We screened patients with catheter ablation for AF, in sinus rhythm at 3 months post-ablation, with no significant mitral valve disease (&lt; moderate), and with prospectively measured LA volumes [maximum (LAVI) and minimum volume index] by echocardiography. LAStiffn index was estimated as (E/e’)/LA emptying fraction. Outcome endpoint was AF recurrence up to 14 years post ablation. Results A total of 591 patients with AF ablation were studied (mean age 60±10 years; 25% women; Table1). At 3 months post-ablation, LAVI was 36±10 mL/m2 and LAstiffn was 0.31±0.21 1/%. Compared to males, female patients were slightly older, had more frequently hypertension, congestive heart failure, prior stroke/TIA, higher CHA2DS2-VASc score; they less often had persistent AF, coronary artery disease, or dilated cardiomyopathy. Women also had higher LAstiffn (0.37±0.24 vs. 0.29±0.19, P &lt;.0001, Figure 1), despite similar indexed LA volumes (Table1). Rates of AF recurrence at follow-up (median 7.5 years; 347 patients with events) were higher in women vs. men (Figure 2, left; log-rank P&lt;.001) and persisted after adjustment for age, type and duration of AF, body mass index, cardiovascular risk factors and comorbidities, CHA2DS2-VASc score ≥2, LV ejection fraction, and LAVI (adjusted HR 1.58 [1.20-2.08], P=.001). Overall, LA volumes and LAstiffn were higher in patients with older age and more comorbidities (hypertension, congestive heart failure, coronary artery disease, persistent AF, CHA2DS2-VASc score ≥2, etc; P&lt;.01 for all). At multivariable regression analysis, LAVI and LAstiffn correlated with E/e’, LV size and mass, degree of mitral/tricuspid regurgitation, and LV stroke volume index (only LAVI). In addition, LAstiffn was higher in patients with elevated right ventricular systolic pressure (RVSP) &gt;35 mmHg and increase in RVSP more than 10 mmHg from pre-ablation (P&lt;.0001) (correlation R=0.44, P&lt;.0001). At follow-up, after adjusting for age and LAVI, higher LAstiffn remained associated with AF recurrence in women (P=.02, HR 2.82 per unit change, 95% CI, 1.08-6.72; Figure 2, right), but not in men (P=.30). Conclusions LAStiffn is higher in women vs. men and correlates with burden of comorbidities, aging, diastolic dysfunction and pulmonary hypertension, possibly reflecting more extensive LA myopathy, and potentially contributing to sex differences in AF recurrence.Figure 1Table 1